Critical severity · published Sep 11, 2026
CVE-2026-89492
ocfs2: validate directory-index entry counts when reading metadata
9.8
CVSS
0.6%
EPSS
No
On KEV
Description
In the Linux kernel, the following vulnerability has been resolved:
ocfs2: validate directory-index entry counts when reading metadata
ocfs2_validate_dx_leaf() and ocfs2_validate_dx_root() check the ECC and
signature of an indexed-directory block before it reaches higher-level
callers, but neither validator bounds the ocfs2_dx_entry_list counts
against the capacity of the block that holds them.
ocfs2_dx_dir_search() then walks
for (i = 0; i < le16_to_cpu(entry_list->de_num_used); i++)
dx_entry = &entry_list->de_entries[i];
over de_num_used entries with no bounds check. entry_list is either
dx_leaf->dl_list (from ocfs2_read_dx_leaf) or, for an inline root,
dx_root->dr_entries. A crafted on-disk image can set de_num_used (and
de_count, which is the __counted_by_le() bound of de_entries) to 0xffff
and make the walk read far past the end of the 4KB metadata block, giving
a slab out-of-bounds read reachable from any path lookup, stat() or open()
on an indexed directory once the image is mounted.
Commit 775c17386a6f ("ocfs2: validate dx_root extent list fields during
block read") already bounds dr_list for the non-inline dx_root, but left
the inline dr_entries path and the dx_leaf dl_list unchecked. Add the
same read-time validation for both entry lists: de_count must equal the
capacity of the block (ocfs2_dx_entries_per_leaf()/per_root()) and
de_num_used must not exceed de_count, rejecting corrupted metadata with
-EFSCORRUPTED before ocfs2_dx_dir_search() can walk an out-of-range entry
array.
de_count is always written as exactly the block capacity when a leaf or
inline root is formatted, so the equality check does not reject any valid
image.
Found by 0sec automated security-research tooling (https://0sec.ai).
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
High
Integrity
High
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.6% · higher than 50% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
LI
Linux · Linux
9b7895efac906d66d19856194e1ba61f37e231a4 before aad3129b8e915d0ff492bb7517d825d8490cfdd9; 9b7895efac906d66d19856194e1ba61f37e231a4 before 5e661f55ca8568471fce558effe81cca112f5cb2; 9b7895efac906d66d19856194e1ba61f37e231a4 before fcfcba8fe17dbf2c8805690b8cc25e32d81249a4; 9b7895efac906d66d19856194e1ba61f37e231a4 before b8a5c0c32df2c5b685ceef76ac77e37c7e1dc3ed; 9b7895efac906d66d19856194e1ba61f37e231a4 before bc70726ddad53c7e9a9a85915bf2415b0d4f42f9; 2.6.30 · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-89492
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-89492
git.kernel.org
https://git.kernel.org/stable/c/5e661f55ca8568471fce558effe81cca112f5cb2
git.kernel.org
https://git.kernel.org/stable/c/aad3129b8e915d0ff492bb7517d825d8490cfdd9
git.kernel.org
https://git.kernel.org/stable/c/b8a5c0c32df2c5b685ceef76ac77e37c7e1dc3ed
git.kernel.org
https://git.kernel.org/stable/c/bc70726ddad53c7e9a9a85915bf2415b0d4f42f9
git.kernel.org
https://git.kernel.org/stable/c/fcfcba8fe17dbf2c8805690b8cc25e32d81249a4
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